In general, a microcontroller such as EC/KBC is used to implement a power sequence specification required by a chipset for a personal computer (PC) and a chip constituted as a system-on-a-chip (SoC). In this case, the power sequence is controlled by firmware (FW) control by a microcontroller. By FW control, it is possible to eliminate a disturbance that causes fluctuation in output and to detect slight abnormalities.
However, if a microcontroller is used to implement the above-mentioned power sequence specification, the following problem accompanied with the characteristic of a microcontroller can occur.
A microcontroller has a characteristic that various processes can be executed only while a power source is supplied to the microcontroller itself. Also, a microcontroller needs to execute predetermined processing within the microcontroller itself in order to perform FW control for power sequence. For this reason, when the power sources of all the systems are lost suddenly, for example, when an AC adapter is removed from a PC with the PC powered on, there is a possibility that a microcontroller cannot complete the predetermined processing within the microcontroller executed for performing FW control for power sequence while a power source is supplied to the microcontroller itself. This can cause a problem that the status of a system indicates an abnormality at the time of rebooting the system.
Therefore, it is required to realize a new technology capable of overcoming the above-mentioned problem.